The present invention relates generally to a security document and, more particularly, to a security document having simulated security threads.
Many documents of value, such as bank notes, currency, checks, stock certificates, and bonds, are provided with security features for preventing illicit copying and forgery. One such security feature is the use of security paper that is not widely available and difficult to reproduce. One type of security paper includes threads or filaments of various materials in the paper.
Security threads or filaments included in prior security papers have typically been made of a metallic, colored, transparent, optical, or magnetic material. These materials can provide effective anti-copying functions, as well as permitting documents to be checked for authenticity by machine or visual inspection. The filaments can be embedded into the security paper during the manufacture thereof, or added to less expensive paper after the paper has been manufactured.
As is known, various compositions can be applied to a cellulosic substance to make it relatively transparent. For example, U.S. Pat. Nos. 5,418,205, 6,103,355, and 6,143,120 describe the application of solventless transparentizing compositions of the type used in the present invention to a cellulosic substrate to transparentize a portion of the substrate. In each of these references, the transparentized portion defines an area in the cellulosic through which text can be viewed. A transparentized portion of a substrate permits an addressee""s name and address to be read through the substrate which is a part of an envelope or mailer.
It is also known that security paper can be produced by transparentizing selected areas of the paper. For example, U.S. Pat. No. 5,989,389 provides a method of producing visible, continuous streaks and/or delimited fields in paper. This paper is particularly useful for bank notes. However, the method of the ""389 patent does not employ a transparentizing composition. Instead, this method produces transparent streaks in the paper by depositing in the streak area a special paper stock that contains fibers which differ from the surrounding cellulosic material.
Further known are security documents that can be manufactured by applying a transparentizing resin to at least a portion of a substantially unfinished porous absorbent sheet to define a transparent region, pattern, or series of streaks. U.S. Pat. No. 5,928,471. The transparentizing resin used in the method of the ""471 patent differs from the transparentizing composition of the present invention. Further, the transparentizing resin of the ""471 patent is applied to a series of discrete areas in the substantially unfinished cellulosic sheet which are at least partially of a lower grammage than the surrounding area.
U.S. patent application Ser. No. 09/300,118 teaches the application of the transparentizing composition of the present invention to a cellulosic substrate in a predetermined pattern, so as to create a relatively transparent graphical image, such as a watermark, for security documents. However, neither the ""471 patent nor the ""118 application teaches a security document that is formed by applying a transparentizing material to a finished cellulosic substrate in thin lines to create simulated security thread in the document.
It would be desirable to manufacture an alternative type of security document embodying simulated security thread as a security feature. It would also be desirable to manufacture a security document with simulated security thread by application of a transparentizing composition in thin lines, rather than embedding an actual security thread or filament in the substrate. Accordingly, there is a need in the present art to develop an alternative security document with enhanced features that are effective in preventing forgery and illegal copying thereof.
The present invention meets that need by providing a security document comprising a finished cellulosic substrate. In accordance with one embodiment of the present invention, the security document comprises a finished cellulosic substrate having at least one transparentized portion formed therein. The substrate defines first and second major surfaces. The transparentized portion comprises a transparentizing composition applied to at least one of the first and second major surfaces of the substrate so as to define an area of increased transparency. The area of increased transparency includes at least one thin line and resembles a simulated security thread. Alternatively, the transparentizing composition can be applied to at least one of the first and second major surfaces of the substrate to define a plurality of thin lines.
The substrate can be comprised of a material selected from the group consisting of wood pulp fibers, vegetable fibers, plant fibers, plastics, synthetics, and polymeric films, and combinations thereof. The substrate can comprise either a web of material or individual cut sheets, and can further comprise printed indicia on at least one of the first and second major surfaces.
In one embodiment of the present invention, the substrate defines an area of reduced thickness. This area of reduced thickness defines the transparentized portion and can lie on the first major surface, or both the first major surface and the second major surface. The transparentized portion of the present embodiment defines the simulated security thread. It has a higher density than and does not exceed the thickness of the reminder of the substrate.
In accordance with yet another embodiment of the present invention, the area of reduced thickness may define a groove in the substrate. This groove can be slightly rounded along its top and bottom portions. In accordance with yet another embodiment of the present invention, the groove can have relatively vertical side walls.
The cellulosic substrate may define a textured portion and the at least one line or plurality of lines may be further defined by the textured portion. The textured portion and the transparentized portion may lie in common areas of the substrate. The textured portion and the transparentized portion may define substantially identical boundaries and may be positioned in substantial alignment on the substrate. The textured portion may define a variable thickness profile across which is applied the transparentizing composition such that the area of increased transparency defines a varying transparency.
The transparentizing composition of the present invention can comprise a radiation-curable composition, or a composition selected so as to cure upon contact with the substrate. In accordance with yet another embodiment of the present invention, the transparentizing composition can further comprise a security agent. The security agent can comprise a photochromic agent, a thermochromic agent, a fluorescent agent, a coloring agent, a fragrance, a UV ink, an optically variable ink, or a combination thereof.
In accordance with yet another embodiment of the present invention, the transparentized portion further comprises a printed portion. The printed portion comprises printed matter, which can comprise a line of text written in white ink, thermochromic ink, photochromic ink, or combinations thereof. In the present embodiment, the printed matter can be either completely or partially covered by the transparentizing composition. The printed matter can lie in the area of reduced thickness of the substrate, and may comprise an amount field of a negotiable document or some other secure data field.
In yet another embodiment of the present invention, the at least one thin line can comprise a first simulated security thread and a second simulated security thread. The first and second simulated security threads can be formed on the same major surface of the substrate and may also overlap. The first and second simulated security threads of the present invention can be a first color and a second color. The first color can be different than the second color.
The simulated security thread of the present invention can be linear or curvilinear. The curvilinear simulated security thread can be asymmetrical. The simulated security thread can be of varying width, as well as discontinuous, or can comprise a plurality of individual discrete simulated security threads. The simulated security thread can extend in a direction which is parallel to a machine direction of the substrate. Alternatively, the simulated security thread can extend in a direction which is parallel to a cross-web direction of the substrate, or interspersed along a machine direction and a cross-web direction of the substrate, or extend in a direction which is diagonal between a machine direction and a cross-web direction of the substrate.
In accordance with yet another embodiment of the present invention, a security document is provided, comprising a finished cellulosic substrate having at least one transparentized portion formed therein. The substrate defines first and second major surfaces. The transparentizing portion comprises a transparentizing composition applied to at least one of the first and second major surfaces to define an area of increased transparency in the substrate, resembling a simulated security thread. The transparentizing composition comprises at least one compound selected from compounds of the formula: 
wherein,
Rxe2x80x3 is any mono- or polyfunctional organic radical;
R is H or CH3;
Rxe2x80x2 is H or xe2x80x94C(O)C(R)xe2x95x90CH2 with the proviso that xe2x80x94C(O)C(R)xe2x95x90CH2 occurs at least once;
x is an integer 0-4 and indicates the number of functional groups on Rxe2x80x3 which are reactive with ethylene or propylene oxide;
z is an integer 1-4 and may vary independently of x and n;
n is an integer 1-20 and is independent of x and z; and
wherein if any of R, Rxe2x80x2, or Rxe2x80x3 are greater than one, their identities and the number of each may be the same or different; or 
wherein,
Rxe2x80x3 is any mono- or polyfunctional organic radical;
R is H or CH3;
Rxe2x80x2 is H or xe2x80x94C(O)C(R)xe2x95x90CH2 with the proviso that xe2x80x94C(O)C(R)xe2x95x90CH2 occurs at least once;
x is an integer 0-4 and indicates the number of functional groups on Rxe2x80x3 which are reactive with ethylene or propylene oxide;
z is an integer 1-4 and may vary independently of x and n;
n is an integer 1-20 and is independent of x and z; and
Rxe2x80x2xe2x80x3 is H or a group of the formula: 
wherein R, Rxe2x80x2, and n are as defined as above, wherein if any of R, Rxe2x80x2, Rxe2x80x3 or Rxe2x80x2xe2x80x3 are greater than one, their identities and the number of each may be the same or different.
In accordance with yet another embodiment of the present invention, a security document is provided, comprising a finished cellulosic substrate having at least one transparentized portion formed therein. The substrate defines first and second major surfaces. The transparentizing portion comprises a transparentizing composition applied to at least one of the first and second major surfaces to define an area of increased transparency in the substrate, resembling a simulated security thread. The transparentizing composition comprises:
i) a cationic catalyzable constituent selected from 1) a vinyl ether, 2) a polyepoxide, 3) a mixture of vinyl ethers, 4) a mixture of polyepoxides, or 5) a mixture of at least one of a vinyl ether and at least one of a polyepoxide;
ii) a free radical catalyzable constituent selected from at least one compound of the formula: 
wherein,
Rxe2x80x3 is any mono- or polyfunctional organic radical;
R is H or CH3;
Rxe2x80x2 is H or xe2x80x94C(O)C(R)xe2x95x90CH2 with the proviso that xe2x80x94C(O)C(R)xe2x95x90CH2 occurs at least once;
x is an integer 0-4 and indicates the number of functional groups on Rxe2x80x3 which are reactive with ethylene or propylene oxide;
z is an integer 1-4 and may vary independently of x and n;
n is an integer 0-20 and is independent of x and z; and
wherein if any of R, Rxe2x80x2, or Rxe2x80x3 are greater than one, their identities and the number of each may be the same or different; and
iii) a catalyst constituent selected from 1) a free radical catalyst, 2) a mixture of free radical catalysts, 3) a living cationic catalyst, 4) a mixture of living cationic catalysts, or 5) mixtures of at least one of a free radical catalyst and at least one of a living cationic catalyst.
In accordance with yet another embodiment of the present invention, a security document is provided, comprising a finished cellulosic substrate having at least one transparentized portion formed therein. The substrate defines first and second major surfaces. The transparentizing portion comprises a transparentizing composition applied to at least one of the first and second major surfaces to define an area of increased transparency in the substrate, resembling a simulated security thread. The transparentizing composition comprises at least one monomer, selected from the group consisting of acrylic esters of polyhydric alcohols, methacrylic esters of polyhydric alcohols, and vinyl ethers.
In accordance with yet another embodiment of the present invention, a security document is provided, comprising a finished cellulosic substrate having at least one transparentized portion formed therein. The substrate defines first and second major surfaces. The transparentizing portion comprises a transparentizing composition applied to at least one of the first and second major surfaces to define an area of increased transparency in the substrate, resembling a simulated security thread. The transparentizing composition comprises a polymer consisting of aliphatic monomers selected from the group consisting of acrylic esters of polyhydric alcohols, methacrylic esters of polyhydric alcohols, and vinyl ethers.
Accordingly, it is a feature of the present invention to enhance document security by applying at least one thin line of a transparentizing composition to a finished cellulosic substrate to simulate a security thread. This feature will provide enhanced document security without having to embed an actual thread or filament in the substrate. Therefore, the simulated security thread of the present invention can provide significant cost savings as compared to conventional security paper with embedded threads or filaments. Further, it is a feature of the present invention to realize improved economics by (i) enabling the production of a security document that includes lines which resemble simulated security threads on bond paper stock as opposed to premium paper stock and (ii) enabling economical customization of simulated security threads.
Further, it is a feature of the present invention to provide a security document including lines on both major surfaces of the cellulosic substrate. Also, it is a feature of the present invention to provide a security document with lines applied in random, opposite directions so that they are non-repeating relative to the printed matter. Moreover, it is a feature of the present invention to provide a security document prepared using printing plates to apply lines that are both horizontal and/or diagonal, relative to the paper web.